U.S. Pat. No. 4,882,826 "Method of Making a Unit Blower Housing", issued to James A. Belanger, Robert J. Wentworth, Barry S. Turner and Graham J. Astley and assigned to Belanger, Inc. of Northville, Mich., discloses a molded plastic housing for an impeller type air blower assembly for use in auto laundries and the like. The housing 13 comprises a generally toroidal portion formed by a circular outer wall 19 which blends into a generally tangential discharge outlet 15. As shown in FIG. 4 of that patent, an electric motor 61 for driving the impeller 25 is mounted on a pad 59. The motor housing 13 is connected to a plate 67 which is secured by bolts to one of the parallel faces of the impeller housing in such a way that the motor shaft 65 extends through a small hole in the impeller housing and into the interior volume of the housing where it is attached to the generally cylindrical impeller 25. Air is drawn into the housing through a relatively large opening 23 in the opposite face of the impeller housing.
Disassembly of the apparatus shown in FIG. 4 of the 862 patent requires that the impeller be removed from the motor drive shaft and withdrawn through the clearance opening 23 before the housing 13 can be removed or replaced. The structure shown in the patent does not permit angular adjustment or rotational adjustment of the impeller housing relative to the motor housing about the axis of the shaft 65 other than to remove the bolts 75 and rotate the housing by the angular distance between the bolt holes.
Although impeller housings and air discharge nozzles can be constructed as separate components joined by bellows type duct joints as suggested in the 826 patent, it has become more common to manufacture the impeller housing and nozzle as a single unit; see for example U.S. Design Pat. No. 315,232 issued Mar. 5, 1991 to James A. Belanger and Graham J. Astley and assigned to Belanger, Inc. of Northville, Mich.